1. Field of the Invention
The present invention relates to devices for high-speed switching of a light beam, in particular when said light beam carries coded data. One of the particular applications of the invention is the switching of light between optical fibers.
2. Description of the Prior Art
A few solutions to the problem of optical switching have already been found but encounter considerable difficulties in regard to their use and potential application to multiple-beam and miniaturization devices, especially when such devices are based on the movements of mirrors controlled by electromechanical impulses.
Devices of the prior art which are worthy of mention include structures which utilize wavelength multiplexing in order to provide subscribers with a number of different services of the videocommunications type on a single multimode optical fiber. These structures are based on the principle of spatial deflection of an optical beam by mirrors which perform the multiplexing functions. These structures entail the need to employ a plurality of optical beams having different wavelengths as well as mirrors consisting of semireflecting plates which introduce losses and have not-negligible dimensions (scarcely less than one square centimeter).
In another known type of device, deflection of light beams is produced by total reflection of light within electrooptical crystals. A device of this type is described in the article entitled "Linear total internal reflection spatial light modulator for laser printing" by Sprague, Turner and Flores, published in the SPIE review, Vol. 229: Advances in Laser Scanning Technology (1981), p. 68-75. The disadvantage of these devices lies in the crystal itself which usually consists of lithium niobate. For reasons of purity, the crystal is available only in small dimensions, which means that the electrodes which are carried by the crystal and serve to apply a control elecric field to this latter will have a very small pitch. In consequence, it will be necessary to provide the device with extensive optical systems. Furthermore, the crystal reacts only slightly to the electric field, thus entailing the need for high control voltages.